2004 4x4 Blazer 5.7 conversion - Blazer Forum - Chevy Blazer Forums

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Old 05-22-2017, 10:15 PM
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Smile 2004 4x4 Blazer 5.7 conversion

So let's have a serious thread that joins a ton of helpful info about swapping a 5.7 into a 2nd gen 4x4... This is more of a discussion thread while fishing for answers at the same time

My 04 is rolling up on 196k miles on the original 4.3, runs great, but is beginning to get up there in mileage, and I keep telling myself that when the 'ol 4.3 begins to tap, knock, or burn a bunch of oil, I'm not putting another V6 in it... For a while I was trying to decide if I wanted to step up to a more current 6.0, but for the cost and sake of being MUCH easier, I think I'm going to opt for a 5.7. But that of course comes with questions...

Yes, there's a literal crap-ton of info scattered all over the interwebs about dropping a 5.7 Vortec into an S10/Blazer, but that's the problem, it's scattered... why can't we just have a single thread with all this helpful info???

So I'm looking to get a few answers to some series questions I have concerning the swap. It's easy to find info on motor mounts, headers, the injector wiring, and so on (but feel free to add in some info here if you have some), it's the smaller overlooked stuff that I'm more concerned about.

For starters, this Blazer is my daily, and I want to keep it that way. The plan is to rebuild the 5.7 fresh. Tear it down to bare block and go from there, put a little cam in it, something that'll turn a head at a red light But leaving stock bore and stroke as I'd like to not have to mess too much with the fuel and ignition system. I want it to be a reliable daily with a little something up it's sleeve, if you know what I mean. I don't want to have the biggest and baddest Blazer out there that runs below 10's in the 1/8 mile, and I know the 5.7 has it's limitations with the stock fuel delivery system.

Some things I have questions about though:

4x4 - still stock IFS, so of course there's oil pan clearance to worry about... With the 5.3/6.0 swaps the Hummer H2 pan is a perfect fit from what I gather, but what can be done with the 5.7? I read something about "extending the 4.3 oil pan", how the heck do you pull that off on a cast-aluminum pan? I'm all about DIY so please inform me lol, but I will have a hard time dropping $300 on an oil pan that fits...

Cooling - I have Dodge Intrepid fans installed already, cools the 4.3 AMAZINGLY well, and leaves tons of wiggle room between the fans and water pump pulley. But is that going to be enough room to drop another 2 cylinders in there? I see people cutting into their radiator support and moving their radiator forward, is that just to clear a stock clutch fan on the front of the 5.7 though maybe?

AC - I live in Florida, so keeping my AC is a MUST... This sort of ties into the above question. If moving the radiator forward is an absolute have-to, what the heck do you do with the condenser at that point?

Oil Filter Cooler Adapter - can this be transferred right over from the 4.3 to the 5.7 to keep all the hoses and filter relocation intact?

EGR - every 5.7 I've seen has it, is this a simple block-off? My 4.3 doesn't have it, don't want to bother adding it lol

Thanks all for any info
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Old 06-02-2017, 10:18 AM
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Hopefully someone that has done one of these swaps themselves will chime in but hopefully I can give you some useful information.

Im not sure about the oil pan because I have never seen a V8 4x4 s10 up close. But since the Vortec V8s still used the steel pans until they swapped over to the LS style engine here is an idea
S-10 Truck 4x4 V-8 Oil Pan Extension, and S10 V8 4x4 Oil Pan, Stealth Conversions

For the cooling systems and swap idea
JTR Chevrolet S-10 Truck . Chapter 16, New Body Style
JTR Chevrolet S-10 Truck . Chapter 16, New Body Style
You can see that the core support has been cut to move the radiator forward. They also used a corvette radiator which is a little thinner/smaller and fits easier
You also might have to modify the hood latch to clear the condenser.

I would delete the oil cooler when you swap to the V8 so you don't have to worry about it.

For the EGR, you can just buy a block off plate to remove it. Just google something like "1997 5.7 vortec egr block off plate" and you will see what I am talking about.
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Old 03-11-2018, 09:04 PM
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This is an LS Swap but it may give you ideas and things to look out for. I'll be following you since my situation is very similar to yours. I have already bought some '99 Camaro exhaust manifolds,cut off the collector flanges and EGR piping and welded them up. https://www.powernationtv.com/episod...o-big-ls-power
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